Abstract
Introduction: The 21-gene recurrence score assay (RSA), a genomic tool to personalize therapy, avoiding over and undertreatment of breast cancer (BC) patients (pts), is available in Portugal since 2012. We aimed to characterize the population of pts with BC whose tumors were tested from 2012 until Dec 2021, analyzing prescription patterns and invasive disease-free survival (iDFS). Methods: Observational, multicenter nationwide retrospective cohort study of pts with RH+/Her2-neg invasive BC treated by upfront surgery, in whom the RSA was performed. The cohort was identified by the national representative of the RSA manufacturer and clinical data was retrospectively collected from medical records by independent investigators. Results: 1119 pts from 36 centers were preregistered. We weren’t able to retrieve data from 7 patients; 21 pts were excluded due to insufficient clinical-pathological information; 7 were excluded for insufficient tissue, and 1 was staged pN2. Thus 1083 pts (91%) were included in the analysis: pN0 - 832 pts (76,8%), pN1 - 238 pts (22%) and pNx -13 pts (1,2%). In pN0 group 57.2% of pts were postmenopausal. Tumors were mostly no special type (NST, 76.6%), G2 (82.9%), with median (med) expression levels of ER 100%, PR 80% and Ki67 25%, pT1 (66.1%), Luminal B like (72.7%) and MINDACT clinical low risk (64.7%). The med RS was 17 (range 0-61). After publication of the TAILORx trial there was an increase in the number of tests per unit of time (248 vs 584); pts and tumor characteristics were similar but for pts > 50 yo with RS ≤ 25 (n= 412) there was an increase in the percentage of pts that didn’t receive adjuvant chemotherapy (ACT, 79.3% vs 96%); for pts ≤50 yo with tumor RS 16 to 25 (n=137) there was an inversion in the percentage of pts treated with ACT (before TAILORx CT 62.2%; after 30%); after TAILORx, 22 of 70 pts ≤50 yo (31.4%) with tumor RS 16-25 who did not receive ACT, received adjuvant ovarian suppression. In pN1 group 64.7% pts were postmenopausal. Tumors were mostly NST (76.5%), G2 (77.3%), with med expression levels of ER 100%, PR 80% and Ki67 17.5%, pT1 (61.8%), Luminal B like (55.5%), high MINDACT risk (85.7%) and with only one positive lymph node (81.9%). The med RS was 15 (range 0-63). 237 of the 238 pts with pN1 disease had the RSA requested before publication of the RxPONDER trial results. 74% of pN1 premenopausal pts with RS ≤ 25 did not receive ACT; 8 of these 54 pts (14.8%) received ovarian suppression. With a med follow-up of 29 months and 16 pts (1,5%) lost to follow up, there were 24 (2%) invasive disease recurrences (17 pN0, 6 pN1 and 1 pNx): 14 distant, 6 locoregional, 3 both and 1 contralateral. Among pN0 pts, 9 pts were premenopausal (med tumor RS of 17, range 7-21), and 2 had received ACT; of the 8 postmenopausal pts (med tumor RS of 25.5, range 10-44), 3 pts had received ACT. 6 pN1 pts recurred - 3 premenopausal with tumor RS of 9, 14 and 15 (1 treated with ACT) and 3 postmenopausal with tumor RS of 23, 28 and 29 (the last 2 treated with ACT). Discussion/Conclusion: In this national cohort, the RSA was requested in mostly hormone receptor (HR)-strongly positive, good prognosis, BC with low risk of early recurrence disease. Pts characteristics are similar to the general characteristics of TAILORx and RxPONDER studies. The analysis of TAILORx suggested potential benefit of ACT in women ≤ 50 yo with tumours RS 16-25; however it did not result in more frequent prescription of ACT after July 2018. There was a high proportion of pN1 premenopausal pts with RS ≤ 25 that did not receive ACT (74%) but almost all pts were tested before the publication of RxPONDER. These results show that real-world studies at a national level are fundamental to evaluate clinical practice, analysing adherence to treatment recommendations and measuring pts outcomes.
Citation Format: Diana Pessoa, Joana Luís, Diogo Alpuim Costa, Mário Fontes e Sousa, Idília Pina, Débora Cardoso, Isabel Andrade, Joana Simões, Ana Ferreira, Renato Cunha, Diogo Branco, José Luís Passos Coelho, for the Portugal "21-Gene Recurrence Score Assay" National Cohort Study. Breast Cancer Recurrence Risk Stratification with the 21-Gene Recurrence Score Assay - the Portuguese National Experience [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P4-11-28.
RSS Feeds